Configuring the Modem
SW3-8 − Carrier Control
SW3-8 ON = Constant
OFF = Switched
SW3-8 selects either constant or switched carrier. Constant carrier allows DTEs, such as asynchronous dumb terminals or RTUs, to operate with modems, without the input RTS signal. When constant carrier mode is enabled (SW3-8 set to ON), the modem forces the transmit carrier active and the RTS-CTS delay is minimum (<0.5 ms.).
You can use constant carrier in 4-wire, point-to-point or multi-point applications (from master to slave modems).
In switched-carrier mode (SW3-8 set to OFF), the RTS/CTS delay is active.
SW3-9 − RX Termination
SW3-9 ON = Enable Rx Termination
OFF = Disable Rx Termination
SW3-9 selects whether RX termination is enabled for a modem. If you set this switch ON, the receiver is terminated with 600 Ω. If you set this switch OFF, the receiver is not terminated.
SW3-10 − Grounding Option
SW3-10 ON = Signal Ground and Earth Ground are Connected OFF = Signal Ground and Earth Ground are Separated
